Index: include/clang/Basic/SourceManagerInternals.h
===================================================================
--- include/clang/Basic/SourceManagerInternals.h
+++ include/clang/Basic/SourceManagerInternals.h
@@ -108,10 +108,9 @@
 
   unsigned getNumFilenames() const { return FilenamesByID.size(); }
 
-  void AddLineNote(FileID FID, unsigned Offset,
-                   unsigned LineNo, int FilenameID,
-                   unsigned EntryExit, SrcMgr::CharacteristicKind FileKind);
-
+  void AddLineNote(FileID FID, unsigned Offset, unsigned LineNo, int FilenameID,
+                   unsigned EntryExit, SrcMgr::CharacteristicKind FileKind,
+                   const SourceManager &SM);
 
   /// \brief Find the line entry nearest to FID that is before it.
   ///
Index: lib/Basic/SourceManager.cpp
===================================================================
--- lib/Basic/SourceManager.cpp
+++ lib/Basic/SourceManager.cpp
@@ -207,13 +207,19 @@
 /// system header or extern C system header.
 void LineTableInfo::AddLineNote(FileID FID, unsigned Offset, unsigned LineNo,
                                 int FilenameID, unsigned EntryExit,
-                                SrcMgr::CharacteristicKind FileKind) {
+                                SrcMgr::CharacteristicKind FileKind,
+                                const SourceManager &SM) {
   std::vector<LineEntry> &Entries = LineEntries[FID];
 
   // An unspecified FilenameID means use the last filename if available, or the
   // main source file otherwise.
-  if (FilenameID == -1 && !Entries.empty())
-    FilenameID = Entries.back().FilenameID;
+  if (FilenameID == -1) {
+    if (!Entries.empty())
+      FilenameID = Entries.back().FilenameID;
+    else
+      FilenameID = getLineTableFilenameID(SM.getFileEntryForID(FID)->getName());
+  }
+  assert(FilenameID != -1);
 
   assert((Entries.empty() || Entries.back().FileOffset < Offset) &&
          "Adding line entries out of order!");
@@ -297,7 +303,7 @@
     EntryExit = 2;
 
   LineTable->AddLineNote(LocInfo.first, LocInfo.second, LineNo, FilenameID,
-                         EntryExit, FileKind);
+                         EntryExit, FileKind, *this);
 }
 
 LineTableInfo &SourceManager::getLineTable() {
Index: test/PCH/line-directive-nofilename.h
===================================================================
--- /dev/null
+++ test/PCH/line-directive-nofilename.h
@@ -0,0 +1,5 @@
+#line 42
+int foo; // This should appear as at line-directive-nofilename.h:42
+
+#line 100 "foobar.h"
+int bar; // This should appear as at foobar.h:100
Index: test/PCH/line-directive-nofilename.c
===================================================================
--- /dev/null
+++ test/PCH/line-directive-nofilename.c
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -emit-pch -o %t %S/line-directive-nofilename.h
+// RUN: not %clang_cc1 -include-pch %t -fsyntax-only %s 2>&1 | FileCheck %s
+
+// This causes an "error: redefinition" diagnostic. The notes will have the
+// locations of the declarations from the PCH file.
+double foo, bar;
+
+// CHECK: line-directive-nofilename.h:42:5: note: previous definition is here
+// CHECK: foobar.h:100:5: note: previous definition is here